The invention relates to a rotary combustor for burning municipal solid waste and more particularly to an improvement in the web between cooling pipes forming the combustor.
Webs disposed between cooling pipes of rotary combustors burning municipal solid waste are subjected to severe operating conditions, high operating temperatures, erosive and corrosive elements in the municipal waste and a gas environment which switches back and forth between being oxidizing and reducing atmospheres resulting in thinning or wasting of the webs. Making the webs thicker only delays replacement and reducing the space between cooling pipes to improve heat transfer causes other problems in the combustion of the waste.
U.S. Pat. No. 4,724,778 describes a rotary combustor in which municipal solid waste is burned in a gas porous cylinder, having a sectioned and compartmented wind box permitting selective delivery of air through the burning waste, above the burning waste, at the start of the burning process and after burning has been well initiated. However the gas porous webs which connect the cooling pipes to form the rotary combustor experience metal wastage and thinning resulting in increased maintenance cost and plant availability losses.